Rotary snap-switch.



J. S. STEWART.

ROTARY SNAP SWITCH.

APPLICATION min nEc.2. ma.

1,171,987. Patented 11eb.15,1916

"UNTER JAMES S. STEWART, OF YORK, N. Y.

non N ROTARY SNAP-SWITCH.,

1,1 71 ,987 Specification of Letters Patent. Patented Feb. 15, 1916.

Application led December 2, 1913. Serial No. 804,278. i

To all fin/tom 'it may concern.'

Be it known that I, JAMES S. STEWART, a citizen of the United States,residing at the city of New York, in the borough of Man hattan and Stateof New York, have invented certain new and useful Improvements in RotarySnap-Switches, of which the following is a full, clear, and exactdescription.

This invention relates to rotary snap switches and is designed primarilyfor v,use with electric lamps, constituting a type of switch, commonlyknown as pull sockets,

in which the cirtiiit controlling mechanism is actuated by a cord orchain depending from the lamp socket.

One object of my invention is to provide a switch which is composed of acomparatively few number of parts of a simple construction, arranged incompact form in an insulating body which completely houses them.

Another object of my invention contemplates an arrangement of the partsof the circuit controller in which the elements constituting the circuitconnections are not suhjected to the strains resulting from the pull onthe chain, whereby the dangerl of the circuit controller becoming easilybroken or getting out of order is substantially eliminated.

With these and other objects which will in` partl be obvious to thoseskilled in the art and will in part be hereinafter set out, my inventionconsists of novel parts, construe tions, combinations and improvementsherein shown and described and particularly pointed out in the appendedclaims.

In the drawings: Figure 1 is an elevation of a complete lamp socketembodying my invention, a portion of the inclosing shell being removedto more clearly show the' socket; Fig. 2 is a view of the bottom of thebase of the socket with the threaded shell removed to show the springdetent; Fig. 3 is a plan of the top of the base of the socket,

the cap being` removed to show lthe circuit controlling mechanism; Fig.4- is a vertical section of the socket on fthe line of Fig'. l; Fig. 5is a vertical section on the line 5--5 of'Fig. 3; Fig. 6 is an end viewof the drum of the circuit controller lookingtoward the left in Fig. 3,the detent coacting therewith being' shown in dotted lines; and Fig. 7is a detail view of the end face of thedrum and the pawl vin theposition and thus prevented from turning while the bolts are threadedinto them. The cap and base are each provided with recesses which form acylindrically-shaped chamber in which is arranged a circuit controllerdrum G. On the periphery of the drum 6 adjacent one of its ends areratchet -teeth 7, which in the usual construction of the drum are fourin number, but any even number of teeth may be used. Contact plates 8are fastened to one face of alternate teeth, which faces arediametrically opposite each other and a metallic band 9 tting in asuitable recess inI the end face of the drum connects these two contactplates together. Mounted on the band 9 coaxially with the axis of thedrum is a pintle 10, the contact plates 8, the band 9 and the pintle l0forming part of the circuit connection and will` be hereinafter referredto. The pintle 10 Vrests in a groove or bearing formed in the base 1,while the abutting face of the cap2 forms the other portion of thebearing; when' the socket is assembled. The other end of the drum 6 isrotatably supported on a stationary shaft l1, one end of which lits intoa longitudinal cylindrical recess in the drum arranged coaxially withthe axis thereof. One end 12 of the shaft 11, is bent at right angles tothe main portion thereof and extends into a cylindrical recess 12 formedin the base 1. The portion of the base between this recess and thechamber for the drum has a groove 10, which forms a seat for'the shaft11 and prevents any lateral movement thereof.

The drum 6 and associated parts, together with terminal plates comprisethe circuit connections whereby current is supplied to the lamp as willnow be described. Mounted in a rectangular recess in the exteriorcylindrical wall of both the cap and base, is a rectangularly-shapedterminal plate 13, the upper end of which has an offset piece 14provided with a threaded---openng into vsa Whichvis threaded a screw 15mounted in a Arecess in thecap 2, which securely fastens 'the plate tothe cap. One side of the plate 14 is slightly offset and carries abinding post 15 to which one lof the supply conductors (not shown) isfastened, the cap 1 being provided with a suitable groove 17, forthesupply conductor which passes down be tWeen the socket and theexteriorshell. To the other side of the plate 13, is attached a lug 18preferably integral therewith which lug is bent over to a position inparallelism with the plate and preferably spaced a slight distancetherefrom. The fiat portion of the lug 18 is opposite a circular opening19 in the plate 13 in which the pintle 10 is rotatably supported, thelug forming an end thrust plate against which the end of the pintle isheld in good electrical contact by means which will hereinafter bereferred to.

The-bottom of the base is divided into two substantiallysegmental-shaped surfaces 20 and 21, the surface 20 having a rectangularportion 22 projecting therefrom. and centrally disposed with respect tcthe socket, the segmental-shaped surface 20 and the projecting part of22 being raised suffi 'ciently abovetheplane of the surface 21 so thatthe central contact which will be hereinafter described, will alonecontact with the center Contact of the lamp bulb 1n ac cordance with theordinary construction of lamp sockets.

' A rectangular slot 24 leads from the surface 21 to thesemi-cylindrical chamber in the base 1. Projecting into this slot is a.spring detent 25which consists of a dat plate adapted to rest againstthe segmental. shaped surface 21, the plate having formed integraltherewith, a spring or contact blade 27, which is adapted to engage withthe teeth 7, and the contact surfaces 8..

The flat plate of the spring detent 25 is maintained in position againstthe base 1 by a metallic shell 28 which forms a part of the electriccircuit and which is closed on one end, the closed end being' cut awayto permit the shell to rest on the segmental shaped surface 21, and toprevent'electrical contact with the center Contact which willhereinafter be referred to. The shell 28 is threaded to form a socketinto which the lamp bulb is screwed as in the usual con.- struction andforms one terminal 0f the lamp.

The shell 28 and detent 25 are held in place on the bas'e by the bolts 3which pass through openings in the, shell and detent plate respectively.

The other supply conductor (not shown) is carried down inside of anexterior shell in a recess 29 formed in the peripheral Walls of the capand base and the conductor is fastened to a terminal plate 30 having anoffset piece 3l fitting in the recess 29, prowhich it is held by a screw33 mounted in The short arm` 34 a recess in the base 1.

rests on the face of the projecting portion 22 and constitutes thecentral contact, which isl adapted to engage with the center contact ofthe lamp (not shown) and forms the other terminal of the lamp.

Ratchet teeth 35 are cut on one of the end faces of the drum, whichteeth are equal in number to the number of teeth 7. The particularformation of these teeth form=one of the important features of theinvention and as shown they do not extend to the recess in which theshaft 11 fits but to an annular boss` 36 formed on the end face of thedrum which boss surrounds the recess referred to.

The faces of the teeth 35 are inclined to a.y

plane perpendicular to the axis of the drum while the edges of the teethlie substantially in this plane, with the boss 36 projecting slightlybeyond it. A. pawl 37 bent at its upper end to engage the teeth 35 isprovided,l with zin-opening 39 of larger diameter than the shaft 11which passes therethrough to permit the pawl to rock or tilt as well asto rotate thereon, the annular boss 36 having a rounded surface againstwhich the pawl 37 bears to normally prevent the pawl from being pressedinto firm engagement with the teeth 35 and acting as a fulcrum. on whichthe pawl canL tilt as will be clear from the operation of the device.The pawl 37 is provided with an offset ear 38 projecting from the upperend of the pawl.

A pull chain 40 is attached to the ear 33 by passing the filamentbetween the two end beads of the chain, through a slot in the ear, thecup-shaped ear forming a seat for the end bead. A coiled spring 42 ismounted on a shaft 12 and in the groove 10', one end thereof being fixedin the recess alongside the bent end 12 of the shaft, while the otherend of the spring engages'with the offset ear 33 and rests against thepull chain 40 to hold the same securely attached to the pawl. The endcoil or convolution of the spring abuts against the end of the groove 10and exerts a pressure on the drum, to maintain the pintle 10 against thelug 13. This spring serves four functions; first, by itsengage ment withthe pawl 37, it maintains it under a torsional stress, so that after a'.pull on the chain 40, the pawl will return to 'position against ashoulder 44 on the face of the base 1 (see Fig. 4) g second, it holdsthe pawl 37 against the boss 36 of the drum and thus maintains the pawlin loose engagement with the teeth 35; third, the spring exerts itstension to continually urge the drum. (l and the pintle 10 against thelug 1S, carried by the terminal plate 13 t0 maintain these parts in.

llt

. drum for a purpose which will be later referred to. Non-circularrecesses 46 are cut in the grooves 45 adjacent the peripheral walls ofthe cap and base and a metallic bell or funnel 47 provided with flanges4S corresponding in shape to the non-circular recesses 46 is heldsecurely in place therein when the cap and base sections are united.l

This manner of securing the bell or funnel in place provides a simple,and convenient construction, which facilitates the assembling of thesocket.

The .completed socket is inclosed in the usual exterior shell comprisinga body portion 49 anda cap 50 which are locked together by any form of alocking joint, the

` body portion 49 being provided with a slot in which .the bell orfunnel 47 rests.

To assemble the socket, the terminal plate 30 is first secured to thebase l. The drum .6, shaft 11, spring 42 and pawl 37 to which the pullchain 40 has been attached, are sep; aratelytassembled and then placedin the chamber in the base l, one end of the spring 42 and the bent end12 of the shaft 1-1 fitting in the recess 12 in the base. The other endof the spring 42 is then fastened over` the offset ear 38 which willmaintain the pawl 37 under tension. The spring detent 25 and the shell28 are then placed in position on the segmental-shaped surface 21. andthe cap and base portions united by the bolts 3. However, beforevunitingthe cap and base portions, the funnel 47 is placed in the recesses inthe abutting faces of these portions and when the cap and base sectionsare united, will'be held in place. Finally,

V-theterminal plate 18 is fastened to the cap by the screw 15. Therecesses in the base and cap are then filled with cement in the usualmanner, the conductors attached to iso the terminal plates and theexterior shell placed over the complete socket.

The pawl 37, when the parts are assembled in this manner, wil-l be heldagainst the boss 36 and will be prevented from pressing against thefaces of the teeth 35 by the spring 42 and due to the torsional force ofthis spring the pawl will be forced against the shoulder 44 on the faceof thel base (see Fig. 3). If'the chain 40 is now pulley to actuatethecircuit controller, the force Willnot be directed perpendicular to theaxis of the shaft 12 since the grooves 45 and the bell or funnel 47through which the chain passesvare at an angle thereto. The pull will'therefore have a component tending to pull the end of the pawl 37, towhich this chain is attached toward the teeth The pawl will therefore berocked on the rounded surface of the boss 36 which will permit the upperend of the pawl to firmly engage with one of the teeth This movement ofthe pawl is facilitated by the arrangement of the offset ear 38 forsince this ear projects laterally from the upper end of the pawl, theangle at which the pull chain lies with respect to the planeperpendicular to the axis of the drum is increased. The lower end of thepawl will also be forced laterally with respect to the shaft l2, againstthe tension of the spring 42, but this tension will not be sufficient toprevent the engagement of the pawl with the teeth and the drum will herotated. At the end of the pull, the pawl S7 and chain 40 are inalinement. lt is in this position that the strains resulting from toostrong a pull on the chain will be im`,.iarted to the circuitcontroller, but since tht` pawl and chain are in alinement, the stressof the pull will occur entirely on these parts and the shaft ll which isseated in the groove l0 is prevented from lateral 1nove ment, so that itwill take the brunt of the pull. It will therefore be seen that thestress resulting from the pull does not occur on the drum 6, the springdetent or any by the pawl 37 the spring detent 25"will.

snap -into engagement with one of the teeth 7 and if the blade 26 is incontact with one` of the contact surfaces 8, the circuit will becompleted to the lamp as follows; terminal plate 13, plug 18, pintle 10,contact 'surface 8, detent 25, shell 28, which forms one terininal ofthe lamp through the lamp to center contact 34 and terminal plate o0 tothe other conductor, when the detent'25 is in engagement with alternateteeth, the circuit will be broken between contact surface 8 and thedetent. leased, the spring 42 will again exert its force against thepawl 37, to press the same against the boss 36, and withdraw the bentend of the pawl from frictional engagement with one of the inclinedfaces of the teeth 35 (see Fig. 7). The torsion ofthe spring will thenreturn the pawl 37 to its normal position against the shoulder 44, withcornparatively little frictional contact between the pawl and theinclined faces of the teeth on the drum for as the pawl returns to itsnormal position, the bent end of the pawl will engage only with thepoint of the tooth.

The strength of the spring necessary to return the pawl to its originalposition when teeth 35 are of the construction delf the chain 4() is nowre-' scribed, is much less than the strength of tlespring required toreturn. the pawl to its normal position Where the pavvl ridesover theinclined surfaces of the teeth and forthis reason, I find the .abovedescribed construction preferable, as one of the essential ,features ofpull sockets of this type is to provide a construction in. which' thelamp socket may be readily manipulated with a slight pull on the chain.

While I have illustrated and described the rotary snap switch incombination with a pull socket yet' it is not my intention to limit theinvention `to this particular type of switch as the drum circuitcontroller and actuating mechanism are' equally applicable to othertypes of switches Where the pavvl 37 may be actuated by a pushrodinstead of 'a pull chain and it is my intention to be limited only tothe scope of the claims appended hereto.

Having thus described my invention., I claim:-

1. In a pull socket, the combination with a drum circuit controllerhaving spaced contacts thereon and a shaft electrically connected tosaid contacts, of a terminal plate having an aperture therein and a lugex tending from said plate opposite said apertion',` a body having achamber therein, a

drum controller in said chamber having spaced contacts thereon, a shaftelectrically connected with said contacts for rotatably supporting oneend of said drum, a second stationary shaft for rotatably supporting theother end of s'aid drum, said shaft having a bent portion inserted in arecess in said body, a terminal plate on said body against which saidfirst named shaft abuts, ratchet teeth on said drum, a paivl mounted onsaid second named shaft for engagement with said ratchet teeth and acoiled spring on said second named shaft, having one end inserted insaid recess, and the other end engaging with said pawl, for maintainingsaid pawl under tension and for forcing said first named shaft againstsaid terminal plate.

3. In a rotary snap sWitch,a circuit controller having a shaft formingpart of the circuit connection., a terminal plate having an vaperturetherein through which said shaft passes, said plate having a lug againstwhich said shaft abuts to maintain electrical contact between the partsand v:means on said plate for securing thereto a conductor Wire.

4. In a pull socket,the combination with a bod, having a chambertherein, a drum circuit controller in said chamber, a shaft forrotatably supporting the same, ratchet teeth. on one end face of thesaid drum, a boss on said facel projecting beyond the plane of saidteeth, a paWl loosely mounted on said. shaft bearing against said boss,a coiled. spring on said shaft bearing against said pavvl, and a pullchain attached to said pavvl passing throughl an opening in said drum,said opening being arranged at an angle to the face of the drum. y f

5. In a pull socket, in combination With a body having a chamber thereinof .a drum circuit controller in said chamber, a shaft for rotatablysupporting one end of said drum, ratchet teeth formed on one end face ofsaid drum, a paWl loosely mounted on said shaft, means including apartvprojecting from the face of said drum normally holding said paWlout of frictional engagement With the inclined faces of `said teeth andmeans including a pull chain for tilting said pawl into engagement withsaid teeth upon the pulling of the chain.

6. In a pull socket, a body of insulating material having a chambertherein, a terminal plate secured to the exterior of said body, a drumcontroller in said chamber having spaced ontacts thereon in electricalconnection with said terminal plate, a plate mounted on the bottom ofsaid body having a contact blade integral therewith extending through anopening in said body andcoacting with the spaced contacts on said drum,a threaded lamp socket secured to the bottoni of said body and holdingsaid plate 10o in place, said socket resting against and in electricalcontact With said plate, a second terminal. plate on said body, saidbody having a projecting lug, said shell having a recess therein throughWhich said lug projects, said last named terminal plate having a portionthereof resting on said lug and out of contact with said socket andforming the center contact for the lamp.

7. In a rotary snap switch, in combina- 11o tion, a body comprising headand base portions having recesses therein forming a chamber, a drumcircuit controller therein comprising a body of insulating material andspaced contacts on said drum, a shaft electrically connected to saidcontacts for supporting one end of said drum and a 'stationary shafthaving one end fitting into a central recess in said drum for supportingthe other end thereof, said last named shaft having its other end bentand fitting into a recess in said base portion, the head portion of saidbody bearing .upon the shaft to maintain it in said `recess.

8. In a rotary snap switclnih combination, a body having a chambertherein, a controller drum in said chamber having spaced contactsthereon, a ,shaft electrically connected to said contacts and passingthrough an aperture in said body,fa\ terminal plate on the exterior ofsaid body having a seat for the end of said shaft and against tion witha body and chamber therein,`of a. drum circuit controller in Saidchamber, a

shaft for rotatably supporting said drum,

ratchet teeth 'formed on one end face of said drum, a pawl looselymounted on said shaft and adapted to engage said ratchet teeth, meansincluding a part projecting from the face of saidcdrum for holding saidpawl out of 'frictional engagement with said teeth, and means includinga member extending exteriorly of said body for tilting said pawl intoengagement with said teeth.

10. In a rotary snap switch, the combination with a body having achamber therein, of a drum circuit controller in said chamber, a shaftfor rotatably 'supporting the same, ratchet teeth on one end face of-said drum, a boss on said face projecting beyond the plane of saidteeth, a pawl loosely mounted .on said shaft, a coil spring surroundingsaid ,shaft and connected t0 said pawl for forc-l ing it into engagementwith said boss and! exerting atension thereon, and a member attached tosaid pawl extending to the eX- terior of said drum for tilting saidp-awl into engagement with said teeth and rotating it against thetension of said spring.

A In witness whereof, I subscribe my signature, in the presence of twowitnesses.

" JAMES S. STEWART.

Witnesses: v

y WALDo M. CHAPIN, i IDA M. Pa'rrnnsorr.v

